1. Field of the Invention
The present invention relates to air conditioning systems, and more particularly pertains to an improved air-conditioning system which utilizes an evaporative precooler to supply a cooled air flow to the compressor of a refrigerant type air-conditioning system. In conventional refrigerant type central air-conditioning systems, a single unit is installed on top of the roof of a building. This allows for economical installation by the builder, but locates the condenser in an environment exposed to extremely hot temperatures. In the arid south western regions of the United States, the temperature on the building roof is frequently over one hundred degrees F. which causes the air-conditioning system to work extremely hard to effectively cool the inside of the house. This results in an inefficient system. Because of the high summertime temperatures and low winds along with a relatively low humidity, the climate of this region is suited for use with evaporative type cooling units. The conventional form of air-conditioning system utilized in these roof mounted applications are rectangular with condenser coils on two sides. A single condenser fan is mounted on the top of this housing and draws ambient air through both of these condenser coil sections and exhausts upwardly through a single circular top opening. The condenser precooler system of the present invention consists of mounting an evaporative precooler over the compressor housing air inlets, or mounting a small down draft evaporative cooler, minus the standard screw cage centrifugal fan and motor, to the top of the refrigerant type AC unit and ducting the cooled air outlet opening into the exhaust opening of the existing condenser fan location. The existing condenser fan is modified by turning over the fan blade so that it pulls the air down through the exhaust hole instead of pushing it out. When the thermostat within the building activates the compressor and condenser fan motors to turn on the same two hundred and thirty volt power that runs the condenser fan will also run a two hundred and thirty volt circulating pump to pump the water from a reservoir over the evaporative cooling pads so that the condenser fan then pushes cooled air pass the condenser coils instead of hot ambient air. This system is extremely simple, and may easily be retrofitted onto existing units. The existing control system does not have to be altered in any way for this precooler system, along with the fact that the existing motor and fan can be used. The major cost involved with a standard evaporative cooler is the motor and screw cage blower assembly. By utilizing the existing condenser cooling fan, these costs are eliminated. A standard quarter inch water line is tapped off an outside valve as in conventional evaporative coolers and is connected to an automatic level float valve arrangement which maintains a water supply reservoir at a constant level.
2. Description of the Prior Art
Various types of air conditioning systems are known in the prior art. A typical example of such an air-conditioning system is to be found in U.S. Pat. No. 2,588,189, which issued to B. Wilson on March 4, 1952. This patent discloses an apparatus for precooling a shipping compartment, such as refrigerator car by circulating chilled fluid in a definite predetermined path and periodically reversing the flow of the fluid through the load. U.S. Pat. No. 2,778,203, which issued to W. Griffith on January 22, 1957, discloses an air-conditioning system having a cooling tower for cooling a condenser through evaporative cooling. U.S. Pat. No. 3,521,460, which issued to J. Knowles on July 21, 1970, discloses a two stage air cooling system which involves precooling the outside air supply entering the building at a central location and then further cooling the precooled air at various local stations corresponding to various parts of the interior of the building as the air is distributed. Chilled water is used as the cooling medium and heat is transferred to the cooler at the local cooling stations first. U.S. Pat. No. 4,295,518 , which issued to G. Rannenberg on October 20, 1981, discloses a combined air cycle heat pump and refrigeration system utilizing air as a refrigerant. A turbo compressor and a regenerative heat exchanger are used for both cooling in the refrigeration mode and heating in the heat pump mode. A plurality of valves are arranged so that in the refrigeration mode the refrigerant air operates in a closed dry loop to avoid problems associated with moisture. U.S. Pat. No. 4,347,708, which issued to R. Bussjager on September 7, 1982, a makeup air preconditioner for use with an air-conditioning unit. An add-on preconditioning unit includes a separate vapor compression refrigeration unit for heating or cooling makeup air supply to an air-conditioning system.
While the above mentioned devices are directed to air conditioning systems, none of these devices disclose an evaporative precooling unit for retrofitting on a conventional refrigerant type exteriorly mounted air-conditioning system unit for supplying precooled air to cool the compressor and condenser unit. Inasmuch as the art is relatively crowded with respect to these various types of air conditioning systems, it can be appreciated that there is a continuing need for and interest in improvements to such air conditioning systems, and in this respect, the present invention addresses this need and interest.